Police in Mexico are investigating claims that rival drug gangs are using the internet as a new battle ground.
The Mexican president wants to crack down on drug-linked violence
An official said police were monitoring the pages of YouTube website for bloody video clips and slideshows apparently posted by cartel members.
Some clips contain gruesome scenes of violence, while in others gangsters appear to taunt their rivals. Their authenticity has not been confirmed.
In 2006, more than 2,000 people died in violence linked to Mexican drug gangs.
Some videos on the site show bloodied bodies with signs of gunshot wounds, while others show people praising the heads of rival cartels.
Many of the images are accompanied by songs and raps taunting opposing groups.
"The messages give the impression that members of organised crime are participating," said Jose Luis Manjarrez, a spokesman for the Mexican attorney general's office.
"We can't rule out, but neither can we be totally sure, that this is being used as a form of communication by organised crime."
A spokesman for YouTube said that video showing people getting hurt, attacked or humiliated was not allowed on the site.
Users flagged up inappropriate content, which YouTube then reviewed and removed if it violated the site's policy, he said.
Mexico's new President Felipe Calderon has vowed to curb drug-related violence.
In January, he sent more than 3,000 soldiers to the northern border city of Tijuana to help fight drug trafficking and gang violence. More than 300 people were killed there in 2006.
This came a month after he dispatched 7,000 troops to Michoacan state on the Pacific coast, where more than 500 people died last year.